Elastic sheet articles may find a variety of uses as, e.g., backings for tapes, mechanical fasteners, etc. Some elastic sheet articles are provided as composites of two coverwebs with elastic filaments located between the coverwebs. When the two coverwebs are attached to each other while the elastic filaments are stretched, the finished composite exhibits elasticity if, e.g., the elastic filaments are allowed to relax after the coverwebs are attached to each other.
Some elastic composite articles are provided with cohesive materials to form cohesive elastic composite articles such as those described in U.S. Pat. No. 3,575,782 (Hansen) and U.S. Pat. No. 4,984,584 (Hansen et al.), and those marketed under the tradenames COBAN and VETRAP by 3M (St. Paul, Minn.). Cohesive elastic composite articles are commonly used to provide compressive support for injuries or to hold compresses, medicated pads and the like in place on a human or an animal. The cohesive elastic composite articles preferably do not stick to skin or a variety of other materials (e.g., compresses, medicated pads, etc.) but will cohesively bond to other layers of the cohesive elastic composite article with sufficient force to hold the contacting layers together against reasonably high shearing forces.
To use the cohesive elastic composite article, a portion of the desired length may be unrolled and separated from the remainder of the composite remaining on the roll. Separation of the elastic composite article can occur before or after the elastic composite article is applied to an individual. Although the elastic composite articles may exhibit relatively straight tear characteristics in the down-web or machine direction, the elastic composite articles exhibit much less desirable tear characteristics in the cross-web or cross-machine direction.
Attempts to tear the elastic composite articles in the cross-web direction can result in jagged or uneven tear lines that extend over a significant distance in the down-web direction as well as in the cross-web direction. Such tear properties are undesirable. As a result, users typically resort to scissors or other cutting tools when separating lengths of elastic composite article from a roll of the elastic composite article. The use of a tool may require the user to let go of the unrolled elastic composite article and/or the roll of elastic composite article.
One attempt to provide desirable cross-web tear characteristics in cohesive elastic composite article materials involves the use of woven or knitted coverwebs. The woven or knitted coverwebs are, however, more expensive than nonwoven coverwebs. As a result, a cohesive elastic composite article including one or more woven or knitted coverwebs is more expensive than a comparable elastic composite article using only nonwoven coverwebs. Another potential disadvantage is that the woven or knitted coverweb may undesirably increase the force required to tear the elastic composite article in the cross-web direction and/or undesirable stiffen the elastic composite article.
Another attempt to provide desirable cross-web tear characteristics in a cohesive elastic composite article involves the addition of a scrim layer (e.g., woven or knitted scrim) that includes fibers or filaments extending in the cross-web direction. The addition of a scrim layer, however, can increase the cost of the elastic composite article and may adversely affect the flexibility or conformability of the elastic composite article, as well as its breathability. Another potential disadvantage is that the scrim may undesirably increase the force required to tear the elastic composite article in the cross-web direction.
Another attempt at providing cross-web tear characteristics to an elastic composite article involves the use of cross-web lines of perforations, with the cross-web lines of perforations located at intervals along the down-web length of the elastic composite article as described in, e.g., International Publication WO 95/06449. The lines of perforations are formed through the entire elastic composite article after it has been assembled.